Missing routines for POSIX:
sem_timedwait: Disabled in libthread for some reason [optional]
we only support the PTHREAD_PROCESS_PRIVATE as process-shared attribute for pthread_barrierattr*() [e.g. in pthread_barrierattr_setpshared()]
sigqueue : optional in 200112, required in 200809. We don't support sigqueue or any posix signal queuing.
mq_notify doesn't support SIGEV_THREAD This would be fairly straightforward to support
aio_notify doesn't support SIGEV_SIGNAL This is blocked by lack of proper SIGINFO
POSIX aio is implemented by wrapping synchronous routines
POSIX aio routines do not perform full set of required tests.
open_memstream seek behaviour is not posix-compliant.